Keeping track of descendants that draw content instead of recalcualting

cc/layers/ui_resource_layer.cc

Index: cc/layers/ui_resource_layer.cc
diff --git a/cc/layers/ui_resource_layer.cc b/cc/layers/ui_resource_layer.cc
index b26ebaa6cceb71fb2c43b53fcbeaf7c289057b56..2794157905170e66fba230d7a11d7dba2d0910bd 100644
--- a/cc/layers/ui_resource_layer.cc
+++ b/cc/layers/ui_resource_layer.cc
@@ -113,11 +113,14 @@ void UIResourceLayer::SetLayerTreeHost(LayerTreeHost* host) {
 
 void UIResourceLayer::RecreateUIResourceHolder() {
   ui_resource_holder_.reset();
-  if (!layer_tree_host() || bitmap_.empty())
+  if (!layer_tree_host() || bitmap_.empty()) {
+    UpdateDrawsContent(true);
     return;
+  }
 
   ui_resource_holder_ =
     ScopedUIResourceHolder::Create(layer_tree_host(), bitmap_);
+  UpdateDrawsContent(true);
 }
 
 void UIResourceLayer::SetBitmap(const SkBitmap& skbitmap) {
@@ -137,12 +140,13 @@ void UIResourceLayer::SetUIResourceId(UIResourceId resource_id) {
     ui_resource_holder_.reset();
   }
 
+  UpdateDrawsContent(true);
   SetNeedsCommit();
 }
 
-bool UIResourceLayer::DrawsContent() const {
-  return ui_resource_holder_ && ui_resource_holder_->id() &&
-         Layer::DrawsContent();
+void UIResourceLayer::UpdateDrawsContent(bool draws_content) {
+  return Layer::UpdateDrawsContent(draws_content && ui_resource_holder_ &&
+                                   ui_resource_holder_->id());
 }
 
 void UIResourceLayer::PushPropertiesTo(LayerImpl* layer) {